Pressure sensitive shrink label

ABSTRACT

A label for application to a surface having at least one compound curve is provided. The label comprises a heat shrinkable film having an inner surface and outer surface and a layer of pressure sensitive adhesive on the inner surface of the heat shrinkable film.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a division of U.S. patent application Ser.No. 12/237,737 filed Sep. 25, 2008, which is a Continuation-In-Part ofInternational Patent Application No. PCT/US08/59397 filed Apr. 4, 2008,which claims priority from U.S. Provisional Applications Nos. 60/910,282filed Apr. 5, 2007 and 60/938,019 filed May 15, 2007. The entiredisclosures of all of the mentioned applications are incorporated hereinby reference.

TECHNICAL FIELD OF THE INVENTION

This invention relates to pressure sensitive shrink labels. Morespecifically, the invention relates to pressure sensitive labels thathave superior conformability to containers having complex shapes andmethods for applying such labels.

BACKGROUND OF THE INVENTION

It is common practice to apply labels to containers or bottles toprovide information such as the supplier of the container or thecontents of the container. Such containers and bottles are available ina wide variety of shapes and sizes for holding many different types ofmaterials such as detergents, chemicals, personal care products, motoroil, beverages, etc.

Polymeric film materials and film facestocks have been described for useas labels in various fields. Polymeric labels are increasingly desiredfor many applications, particularly clear polymeric labels since theyprovide a no-label look to decorated glass and plastic containers. Paperlabels block the visibility of the container and/or the contents in thecontainer. Clear polymeric labels enhance the visual aesthetics of thecontainer, and therefore the product, and are growing much faster thanpaper labels in the package decoration market as consumer productcompanies are continuously trying to upgrade the appearance of theirproducts. Polymeric film labels also have superior mechanicalproperties, such as tensile strength and abrasion resistance.

Traditional pressure sensitive adhesive (PSA) labels often havedifficulty adhering smoothly to containers having curved surfaces and/orcomplex shapes without wrinkling, darting or lifting on the curvedsurfaces. The label size of typical PSA labels is limited to no largerthan ¼ inch (6.35 mm) away from the edge (beginning) of curvature of acontainer or article. Shrink sleeve labels have typically been used onthese types of compound containers. Labeling operations are carried outusing processes and methods that require the formation of a tube orsleeve of the heat shrink film that is placed over the container andheated in order to shrink the film to conform to the size and shape ofthe container. Alternatively, the containers are completely wrapped witha shrink label using a process wherein the shrink film is applied to thecontainer directly from a continuous roll of film material and then heatis applied to conform the wrapped label to the container. However, labeldefects can occur during labeling operations of simple or compoundshaped bottles during application or in post application processes.These misapplied labels result in high scrap or extra processing stepsthat can be costly.

The present invention provides a pressure sensitive adhesive label thatcan be applied to containers and articles on complex shapes and compoundcurves with less material required and less cost than for shrink sleeveor shrink wrap labels. In addition, the labels of the present inventionenable the user to expand the billboard or graphics region oftraditional pressure sensitive labels on containers and articles havingcomplex shapes and/or compound curves.

SUMMARY OF THE INVENTION

A label for application on a curved or nonplanar surface comprising aheat shrink film and a pressure sensitive adhesive is provided. In oneembodiment, there is provided a pressure sensitive adhesive label forapplication on a surface having at least one compound curve, the labelcomprising: a heat shrinkable film having an inner surface and outersurface, and a machine direction and a transverse direction, the filmhaving an ultimate shrinkage S in at least one direction of at least 10%at 90° C., wherein the shrinkage in the other direction is S±20%; and alayer of pressure sensitive adhesive on the inner surface of the heatshrinkable film. The shrink film has moderate and balanced shrink inboth the machine direction and the transverse direction. In oneembodiment, the film has an ultimate shrinkage S in at least onedirection of at least 10% at 90° C., and the shrinkage in the otherdirection is S±10%. The label may further include a release linerremoval adhered to the adhesive layer.

There is also provided an article bearing a label comprising: an articlehaving a surface comprising at least one compound curve; and a pressuresensitive label comprising a heat shrinkable film having an innersurface and outer surface, and a layer of pressure sensitive adhesive onthe inner surface of the heat shrinkable film, wherein the label isapplied to at least one compound curve.

A method of applying a label to an article wherein the article has asurface having at least one compound curve is provided. The methodcomprises: (a) providing an article having a surface comprising at leastone compound curve; (b) providing a label comprising (i) a heatshrinkable film having an inner surface and outer surface and (ii) alayer of pressure sensitive adhesive on the inner surface of the heatshrinkable film, wherein the label has a central portion and aperipheral portion; (c) contacting the adhesive layer of the centralportion of the label with the article; (d) applying pressure to thelabel in an outward direction from the central portion to the peripheralportion, wherein at least a portion of the label is applied to at leastone compound curve of the article; and (e) applying heat to at least aportion of the label to shrink at least that portion of the label andadhere the label to the article. After or during the application ofheat, the label may be further compressed or wiped down to fully adherethe label to the article and eliminate any remaining defects in thelabel.

In one aspect of the invention, there is provided a method of applying alabel to an article, the method including the steps of: providing anarticle having a surface including at least one compound curve;providing a label including (i) a heat shrinkable film having an innersurface and an outer surface; and (ii) a layer of pressure sensitiveadhesive on the inner surface of the heat shrinkable film, wherein thelabel has a first edge and a contact region; contacting the adhesivelayer in the contact region with the article; applying heat and pressuresimultaneously to the label in a direction from the contact region tothe first edge such that the first edge of the label adheres to articleand the label shrinks to conform to the compound curve of the article,wherein the heat and pressure are applied by a heated conformablemembrane.

The heated and pressure is applied to the label, in one embodiment, by awalking beam that includes a conformable heated bladder. The heatedbladder may be expandable.

In another embodiment, heat and pressure are applied by a walking beamthat includes a heated cavity wherein the shape of the cavitycorresponds to the shape of the article to which the label is applied.

In one embodiment, heat and pressure are applied by a walking beam thatincludes a flexible heated membrane suspended between at least two framemembers. The heated membrane may be porous or non-porous. The porousmembrane may include a mesh screen.

In yet another embodiment, heat and pressure are applied by a walkingbeam that includes a flexible heated membrane mounted to a rectangularframe. The walking beam may alternatively include a flexible heatedmembrane mounted to a frame having a shape corresponding to the shape ofthe article to which the label is applied.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a front view of a container to which the label of thepresent invention has been applied as compared to prior art pressuresensitive labels.

FIG. 2A to 2D illustrates the labeled container before and after theapplication of heat to the label.

FIG. 3A to 3D illustrate embodiments of containers having complex shapesand compound curves to which the label of the present invention isapplied.

FIGS. 4A and 4B illustrate front views of embodiments of containershaving irregular surfaces.

FIG. 5 is a three dimensional view of a portion of a labeled articlehaving a compound curve.

FIGS. 6A-6D schematically illustrate the process of applying the labelto an article having a compound curve.

FIGS. 7A and 7B schematically illustrate an embodiment of the process ofapplying a label to an article wherein a walking beam is used.

FIG. 8 is a top view of a walking beam conveyor having a heated bladder.

FIGS. 9A and 9B are a schematic view of a heated cavity containment boxof a walking beam conveyor.

FIG. 10 is a schematic view of a walking beam conveyor arm having adraped flexible membrane.

FIGS. 11A and 11B are schematic views of a rectangular framedcontainment box of a walking beam conveyor having a heated membrane.

FIGS. 12A and 12B are schematic views of a framed containment box of awalking beam conveyor having a heated membrane, wherein the shape of theframe corresponds to the shape of the article to be labeled.

FIG. 13 is a schematic view of a walking beam conveyor having a porousmembrane.

FIGS. 14A and 14B are side views of a walking beam containment boxincluding an expandable bladder.

DETAILED DESCRIPTION OF THE INVENTION

Pressure sensitive adhesive labels are provided that can improve theappearance of labeled containers and articles by conforming to thecontours of the container or article and by providing an enlargedbillboard appearance. End users and product designers must currentlyalter their designs to accommodate the limitations of traditionalproduct decorating technologies. The labels of the present inventionprovide the designers with more freedom in product designs to createmore shelf appeal and to carry more information.

Containers and articles with compound curves typically have to be fullywrapped with shrink film in order to label or decorate the article. Thelabels of the present invention are capable of expanding the label overcomplex curves without having to fully wrap the article. This partiallabel coverage impacts the product cost as well as the productappearance. Typical pressure sensitive labels cannot be applied tocontainers and articles without undesirable darting and wrinkling of thelabel. “Darting” is defined as the accumulation of excess label materialthat rises up away from the article to which the label is applied.

The labels of the present invention provide significant processingadvantages over traditional shrink labels. For example, the pressuresensitive shrink labels of the present invention allow for moretraditional printing and secondary processes such as foils and hotstamping. Where typical shrink labels must be subsurface printed, thelabels of the present invention can be surface printed, which enhancesthe color quality, sharpness and texture of the printed image. The labelfilm may be printed by water flexographic, UV flexographic, UVletterpress, UV screen, solvent gravure and hot foil stamp.

The pressure sensitive labels comprise (a) a heat shrinkable polymericfilm having an inner surface and an outer surface and a machinedirection and a transverse direction; and (b) a layer of pressuresensitive adhesive on the inner surface of the heat shrinkable film. Theshrinkage of the heat shrinkable polymeric film is balanced in themachine direction and the transverse direction. In at least onedirection, the ultimate shrinkage (S) is at least 10% at 90° C. and inthe other direction, the shrinkage is S±20%. As an illustration ofbalanced shrinkage, if the shrinkage in the machine direction is 40% at105° C., then the shrinkage in the transverse direction is 40%±20%, orwithin the range of 20% to 60% at 105° C. In one embodiment, theultimate shrinkage (S) is at least 10% at 90° C. and in the otherdirection, the shrinkage is S±10%. As used herein, the term “ultimateshrinkage” means the maximum shrinkage the film is capable of achievingat a particular shrink temperature, as measured by ASTM Method D 1204.

The labels are not provided as a shrink sleeve or tube that encapsulatesthe entire article or as a shrink wrap label that wraps around thearticle and forms a seam wherein the ends of the label meet. The presentlabels may be provided in a variety of shapes to suit the article orcontainer to which they are applied, giving the container designergreater latitude in container configuration and label design than withtraditional pressure sensitive labels or with shrink wrap or shrinksleeve labels. The labels may be cut into the desired shape by any knownmethod, including, for example, die cutting and laser cutting. In oneembodiment, the label is die cut to a specific configuration thatcompensates for the shrinkage of the label and the shape of the articleto which it is applied.

Because the label is conformable, the billboard or graphics area of thelabeled container can be extended further onto the container edges andonto compound curved areas of the container. The label may be 10% to 30%larger than a standard PSA label. As used herein, the term “compoundcurve” means a surface having no direction for which there is nocurvature. For example, the surface of a sphere or the surface of anellipsoid has curvature in every direction, and therefore has compoundcurves. A cylinder, on the other hand, has a surface for which there isat least one direction for which there is no curvature. Thus, a simplecylinder does not have compound curves.

FIG. 1 illustrates the expanded billboard area of the pressure sensitiveshrink label of the present invention. Bottle 10 has pressure sensitiveshrink label 12 adhered thereto. The dashed line 14 indicates the outerboundary of standard pressure sensitive labels. A standard (i.e.,non-shrink) pressure sensitive label cannot extend onto the areas of thebottle having the compound curves 16 (the area between the inner dashedline and the outer solid line). When label 12 is initially applied tothe bottle 10, darts and pleats may form near the perimeter of the labelin the areas of the bottle having compound curves 16.

Once the pressure sensitive label is applied to the container, heat isapplied as needed to eliminate any label application defects such asdarts, edge lift and wrinkles. In one embodiment, pressure and/or wipedown may be used in addition to the application of heat to eliminate anydefects.

Referring to FIGS. 2A-2D, the present label and method for applying thelabel are illustrated. In FIGS. 2A and 2B, a label 12 that includes ashrink film having a continuous layer of pressure sensitive adhesiveapplied thereto is applied to a container 10 having compound curvesaround the circumference of the container, and then wiped down. No heatis applied to the label. The label 12 extends onto the compound curves16 where darts 18 are formed near the perimeter 20 of the label. FIGS.2C and 2D show the labeled container of FIGS. 2A-2B after heat isapplied to the label. The darts 18 have been eliminated and the label 12conforms to the compound curves of the container 10 near the labelperimeter 20 without any defects.

The article or container to which the label is applied can be providedin a variety of forms or shapes. Non-limiting examples of suitablearticles include containers with and without closures, trays, lids,toys, appliances, etc. The article or container may be made of anyconventional polymer, glass, or metal such as aluminum. Examples ofsuitable polymeric materials include high density polyethylene (HDPE),low density polyethylene (LDPE), polyethylene terephthalate (PET),polypropylene (PP), polyvinyl chloride, polycarbonate, nylon,fluorinated ethylene propylene, polystyrene, etc. The article orcontainer can be made by a number of various processes known in the art,such as blow molding, injection molding, thermoforming, rotationalmolding and the like.

Useful containers include, for example, a bottle having a closure on thetop of the bottle, an upside down bottle having a closure on the bottomof the bottle, a bottle with a pump dispenser or a foaming dispenser, atube with a closure and a bottle with a closure.

The container or article may have a transparent appearance. In oneembodiment, the container or article has a translucent appearance. Thetranslucent appearance can be achieved by, for example, treatments ofthe transparent container or article, the addition of ingredients suchas dyes and pearlescent agents to base polymers, the use ofpolypropylene and/or polyethylene that are mixed with clarifying agents.The treatments include, for example, spray coating, sandblasting, andmold surface treatment.

The container or article may include aesthetic features, including, forexample, textures, embossing, lenticular lens, colors, holograms,frosted or matte color, etc. The surface of the container or article maybe treated prior to application of the label. For example, the surfaceof the container or article may be flame treated or a primer coating maybe applied.

FIGS. 3A, 3B and 3C each illustrate a container having a complex shapeand compound curves. FIG. 3A is a front view of a container 30 a havinga symmetrical, spherical shape wherein the container has a taperedconcave area 32 at the top and a wider convex area 33 toward the bottom.Typically, a shrink sleeve would be used to provide a functional labelfor this container. With the present invention, a pressure sensitiveshrink label 31 can be smoothly applied to container 30 a without theappearance of label defects. FIG. 3B is a front view of a container 30 bhaving an asymmetrical shape wherein one side of the container has botha concave area 34 and a convex area 35 and the opposing side curves in asubstantially similar manner along the length of the container. Theconventional method of labeling container 30 b would be to apply ashrink sleeve label to conform to the complex shape of the container. Apressure sensitive shrink label 31 can be applied to the container 30 bto provide sufficient billboard area with much less label material. FIG.3C is a front view of a container 30 c that is an upside down bottlehaving a closure 36 at the bottom and label 31 applied to the frontsurface. FIG. 3D is a side view of container 30 c. The areas 37 withinthe dashed lines indicate the outer boundaries of standard pressuresensitive labels that can be applied to the container. The complex shapeof this container requires two separate standard pressure sensitivelabels to decorate the container, as the application of one continuousstandard pressure sensitive label would result in the formation of dartsand pleat defects. Pressure sensitive shrink label 31 can cover a muchlarger area, which provides more design options for the productdesigner.

FIGS. 4A and 4B each illustrate a container having an irregular surface.FIG. 4A is a front view of a container 40 a having raised ridges 42along one side of the container. The opposing side of the container hasa smooth surface. FIG. 4B is a front view of a container 40 b havingcircumferentially recessed rings 43 along the length of the container.It should be noted that cylindrically shaped articles having areas ofcompound curves such as containers 40 a and 40 b are not excluded fromthe articles claimed herein.

FIG. 5 is a schematic three dimensional view of a portion of a containerto which the label has been applied. The container 50 has surfacecomprising a compound curve. Label 52 is applied to the container andcovers a portion of the compound curved area. Line 54 indicates theouter boundary to which typical pressure sensitive labels can be appliedwith out the formation of defects in the label. Area 56 indicates theexpanded billboard area that is obtainable with the present labelswithout the formation of defects such wrinkles, edge lift or darts.

Shrink Film

The polymeric films useful in the label constructions of the presentinvention possess balanced shrink properties. The balanced shrinkproperties allow the film to tighten darts and wrinkles initially formedin the label when the label is applied over curved surfaces and allowthe darts and wrinkles to be wiped down with minimal graphics distortionof the label. Films having unbalanced shrink, that is, films having ahigh degree of shrink in one direction and low to moderate shrink in theother direction are not particularly useful because while darts may beremoved in one direction, in the other direction the formation of dartsis exacerbated. Useful films having balanced shrink allow for a widervariety of label shapes to be applied to a wider variety of containershapes.

In one embodiment, the polymeric film has an ultimate shrinkage (S) asmeasured by ASTM procedure D1204 in at least one direction of at least10% at 90° C. and in the other direction, the shrinkage is S±20%. Inanother embodiment, the film has an ultimate shrinkage (S) in at leastone direction of about 10% to about 50% at 70° C. and in the otherdirection, the shrinkage is S±20%. In one embodiment, the ultimateshrinkage (S) is at least 10% at 90° C. and in the other direction, theshrinkage is S±10%. The shrink initiation temperature of the film, inone embodiment, is in the range of about 60° C. to about 80° C.

The shrink film must be thermally shrinkable and yet have sufficientstiffness to be dispensed using conventional labeling equipment andprocesses, including printing, die-cutting and label transfer. Thestiffness of the film required depends on the size of the label, thespeed of application and the labeling equipment being used. In oneembodiment, the shrink film has a stiffness in the machine direction(MD) of at least 5 mN, as measured by the L&W Bending Resistance test.In one embodiment, the shrink film has a stiffness of at least 10 mN, orat least 20 mN. The stiffness of the shrink film is important for properdispensing of labels over a peel plate at higher line speeds.

In one embodiment, the die-cut labels are applied to the article orcontainer in an automated labeling line process at a line speed of atleast 100 units per minute, or at least 250 units per minute or at least500 units per minute.

In one embodiment, the shrink film has a 2% secant modulus as measuredby ASTM D882 in the machine direction (MD) of about 20,000 to about400,000 psi, and in the transverse (or cross) direction (TD) of about20,000 to about 400,000 psi. In another embodiment, the 2% secantmodulus of the film is about 30,000 to about 300,000 in the machinedirection and about 30,000 to about 300,000 in the transverse direction.The film may have a lower modulus in the transverse direction than inthe machine direction so that the label is easily dispensed (MD) whilemaintaining sufficiently low modulus in the TD for conformability and/orsqueezability.

The polymeric film may be made by conventional processes. For example,the film may be produced using a double bubble process, tenter processor may comprise a blown film.

The shrink film useful in the label may be a single layer constructionor a multilayer construction. The layer or layers of the shrink film maybe formed from a polymer chosen from polyester, polyolefin, polyvinylchloride, polystyrene, polylactic acid, copolymers and blends thereof.

Polyolefins comprise homopolymers or copolymers of olefins that arealiphatic hydrocarbons having one or more carbon to carbon double bonds.Olefins include alkenes that comprise 1-alkenes, also known asalpha-olefins, such as 1-butene and internal alkenes having the carbonto carbon double bond on nonterminal carbon atoms of the carbon chain,such as 2-butene, cyclic olefins having one or more carbon to carbondouble bonds, such as cyclohexene and norbornadiene, and cyclic polyeneswhich are noncyclic aliphatic hydrocarbons having two or more carbon tocarbon double bonds, such as 1,4-butadiene and isoprene. Polyolefinscomprise alkene homopolymers from a single alkene monomer, such as apolypropylene homopolymer, alkene copolymers from at least one alkenemonomer and one or more additional olefin monomers where the firstlisted alkene is the major constituent of the copolymer, such as apropylene-ethylene copolymer and a propylene-ethylene-butadienecopolymer, cyclic olefin homopolymers from a single cyclic olefinmonomer, and cyclic olefin copolymers from at least one cyclic olefinmonomer and one or more additional olefin monomers wherein the firstlisted cyclic olefin is the major constituent of the copolymer, andmixtures of any of the foregoing olefin polymers.

In one embodiment, the shrink film is a multilayer film comprising acore layer and at least one skin layer. The skin layer may be aprintable skin layer. In one embodiment, the multilayer shrink filmcomprises a core and two skin layers, wherein in at least one skin layeris printable. The multilayer shrink film may be a coextruded film.

The film can range in thickness from 0.5-20, or 0.5-12, or 0.5-8, or 1-3mils. The difference in the layers of the film can include a differencein thermoplastic polymer components, in additive components, inorientation, in thickness, or a combination thereof. The thickness ofthe core layer can be 50-95%, or 60-95% or 70-90% of the thickness ofthe film. The thickness of a skin layer or of a combination of two skinlayers can be 5-50%, or 5-40% or 10-30% of the thickness of the film.

The film can be further treated on one surface or both the upper andlower surfaces to enhance performance in terms of printability oradhesion to an adhesive. The treatment can comprise applying a surfacecoating such as, for example, a lacquer, applying a high energydischarge to include a corona discharge to a surface, applying a flametreatment to a surface, or a combination of any of the foregoingtreatments. In an embodiment of the invention, the film is treated onboth surfaces, and in another embodiment the film is treated on onesurface with a corona discharge and is flame treated on the othersurface.

The layers of the shrink film may contain pigments, fillers,stabilizers, light protective agents or other suitable modifying agentsif desired. The film may also contain anti-block, slip additives andanti-static agents. Useful anti-block agents include inorganicparticles, such as clays, talc, calcium carbonate and glass. Slipadditives useful in the present invention include polysiloxanes, waxes,fatty amides, fatty acids, metal soaps and particulate such as silica,synthetic amorphous silica and polytetrafluoroethylene powder.Anti-static agents useful in the present invention include alkali metalsulfonates, polyether-modified polydiorganosiloxanes,polyalkylphenylsiloxanes and tertiary amines.

In one embodiment, the shrink film is microperforated to allow trappedair to be released from the interface between the label and the articleto which it is adhered. In another embodiment, the shrink film ispermeable to allow fluid to escape from the adhesive or from the surfaceof the article to escape. In one embodiment, vent holes or slits areprovided in the shrink film

Adhesives

A description of useful pressure sensitive adhesives may be found inEncyclopedia of Polymer Science and Engineering, Vol. 13,Wiley-Interscience Publishers (New York, 1988). Additional descriptionof useful PSAs may be found in Polymer Science and Technology, Vol. 1,Interscience Publishers (New York, 1964). Conventional PSAs, includingacrylic-based PSAs, rubber-based PSAs and silicone-based PSAs areuseful. The PSA may be a solvent based or may be a water based adhesive.Hot melt adhesives may also be used. In one embodiment, the PSAcomprises an acrylic emulsion adhesive.

The adhesive and the side of the film to which the adhesive is appliedhave sufficient compatibility to enable good adhesive anchorage. In oneembodiment, the adhesive is chosen so that the labels may be cleanlyremoved from PET containers up to 24 hours after application. Theadhesive is also chosen so that the adhesive components do not migrateinto the film.

In one embodiment, the adhesive may be formed from an acrylic basedpolymer. It is contemplated that any acrylic based polymer capable offorming an adhesive layer with sufficient tack to adhere to a substratemay function in the present invention. In certain embodiments, theacrylic polymers for the pressure-sensitive adhesive layers includethose formed from polymerization of at least one alkyl acrylate monomercontaining from about 4 to about 12 carbon atoms in the alkyl group, andpresent in an amount from about 35-95% by weight of the polymer orcopolymer, as disclosed in U.S. Pat. No. 5,264,532. Optionally, theacrylic based pressure-sensitive adhesive might be formed from a singlepolymeric species.

The glass transition temperature of a PSA layer comprising acrylicpolymers can be varied by adjusting the amount of polar, or “hardmonomers”, in the copolymer, as taught by U.S. Pat. No. 5,264,532,incorporated herein by reference. The greater the percentage by weightof hard monomers is an acrylic copolymer, the higher the glasstransition temperature. Hard monomers contemplated useful for thepresent invention include vinyl esters, carboxylic acids, andmethacrylates, in concentrations by weight ranging from about zero toabout thirty-five percent by weight of the polymer.

The PSA can be acrylic based such as those taught in U.S. Pat. No.5,164,444 (acrylic emulsion), U.S. Pat. No. 5,623,011 (tackified acrylicemulsion) and U.S. Pat. No. 6,306,982. The adhesive can also berubber-based such as those taught in U.S. Pat. No. 5,705,551 (rubber hotmelt). It can also be radiation curable mixture of monomers withinitiators and other ingredients such as those taught in U.S. Pat. No.5,232,958 (UV cured acrylic) and U.S. Pat. No. 5,232,958 (EB cured). Thedisclosures of these patents as they relate to acrylic adhesives arehereby incorporated by reference.

Commercially available PSAs are useful in the invention. Examples ofthese adhesives include the hot melt PSAs available from H.B. FullerCompany, St. Paul, Minn. as HM-1597, HL-2207-X, HL-2115-X, HL-2193-X.Other useful commercially available PSAs include those available fromCentury Adhesives Corporation, Columbus, Ohio. Another useful acrylicPSA comprises a blend of emulsion polymer particles with dispersiontackifier particles as generally described in Example 2 of U.S. Pat. No.6,306,982. The polymer is made by emulsion polymerization of2-ethylhexyl acrylate, vinyl acetate, dioctyl maleate, and acrylic andmethacrylic comonomers as described in U.S. Pat. No. 5,164,444 resultingin the latex particle size of about 0.2 microns in weight averagediameters and a gel content of about 60%.

A commercial example of a hot melt adhesive is H2187-01, sold by AtoFindley, Inc., of Wauwatusa, Wis. In addition, rubber based blockcopolymer PSAs described in U.S. Pat. No. 3,239,478 also can be utilizedin the adhesive constructions of the present invention, and this patentis hereby incorporated by a reference for its disclosure of such hotmelt adhesives that are described more fully below.

In another embodiment, the pressure-sensitive adhesive comprises rubberbased elastomer materials containing useful rubber based elastomermaterials include linear, branched, grafted, or radial block copolymersrepresented by the diblock structure A-B, the triblock A-B-A, the radialor coupled structures (A-B)_(n), and combinations of these where Arepresents a hard thermoplastic phase or block which is non-rubbery orglassy or crystalline at room temperature but fluid at highertemperatures, and B represents a soft block which is rubbery orelastomeric at service or room temperature. These thermoplasticelastomers may comprise from about 75% to about 95% by weight of rubberysegments and from about 5% to about 25% by weight of non-rubberysegments.

The non-rubbery segments or hard blocks comprise polymers of mono- andpolycyclic aromatic hydrocarbons, and more particularlyvinyl-substituted aromatic hydrocarbons that may be monocyclic orbicyclic in nature. Rubbery materials such as polyisoprene,polybutadiene, and styrene butadiene rubbers may be used to form therubbery block or segment. Particularly useful rubbery segments includepolydienes and saturated olefin rubbers of ethylene/butylene orethylene/propylene copolymers. The latter rubbers may be obtained fromthe corresponding unsaturated polyalkylene moieties such aspolybutadiene and polyisoprene by hydrogenation thereof.

The block copolymers of vinyl aromatic hydrocarbons and conjugateddienes that may be utilized include any of those that exhibitelastomeric properties. The block copolymers may be diblock, triblock,multiblock, starblock, polyblock or graftblock copolymers. Throughoutthis specification, the terms diblock, triblock, multiblock, polyblock,and graft or grafted-block with respect to the structural features ofblock copolymers are to be given their normal meaning as defined in theliterature such as in the Encyclopedia of Polymer Science andEngineering, Vol. 2, (1985) John Wiley & Sons, Inc., New York, pp.325-326, and by J. E. McGrath in Block Copolymers, Science Technology,Dale J. Meier, Ed., Harwood Academic Publishers, 1979, at pages 1-5.

Such block copolymers may contain various ratios of conjugated dienes tovinyl aromatic hydrocarbons including those containing up to about 40%by weight of vinyl aromatic hydrocarbon. Accordingly, multi-blockcopolymers may be utilized which are linear or radial symmetric orasymmetric and which have structures represented by the formulae A-B,A-B-A, A-B-A-B, B-A-B, (AB)_(0,1,2) . . . BA, etc., wherein A is apolymer block of a vinyl aromatic hydrocarbon or a conjugateddiene/vinyl aromatic hydrocarbon tapered copolymer block, and B is arubbery polymer block of a conjugated diene.

The block copolymers may be prepared by any of the well-known blockpolymerization or copolymerization procedures including sequentialaddition of monomer, incremental addition of monomer, or couplingtechniques as illustrated in, for example, U.S. Pat. Nos. 3,251,905;3,390,207; 3,598,887; and 4,219,627. As well known, tapered copolymerblocks can be incorporated in the multi-block copolymers bycopolymerizing a mixture of conjugated diene and vinyl aromatichydrocarbon monomers utilizing the difference in their copolymerizationreactivity rates. Various patents describe the preparation ofmulti-block copolymers containing tapered copolymer blocks includingU.S. Pat. Nos. 3,251,905; 3,639,521; and 4,208,356, the disclosures ofwhich are hereby incorporated by reference.

Conjugated dienes that may be utilized to prepare the polymers andcopolymers are those containing from 4 to about 10 carbon atoms and moregenerally, from 4 to 6 carbon atoms. Examples include from1,3-butadiene, 2-methyl-1,3-butadiene(isoprene),2,3-dimethyl-1,3-butadiene, chloroprene, 1,3-pentadiene, 1,3-hexadiene,etc. Mixtures of these conjugated dienes also may be used.

Examples of vinyl aromatic hydrocarbons which may be utilized to preparethe copolymers include styrene and the various substituted styrenes suchas o-methylstyrene, p-methylstyrene, p-tert-butylstyrene,1,3-dimethylstyrene, alpha-methylstyrene, beta-methylstyrene,p-isopropylstyrene, 2,3-dimethylstyrene, o-chlorostyrene,p-chlorostyrene, o-bromostyrene, 2-chloro-4-methylstyrene, etc.

Many of the above-described copolymers of conjugated dienes and vinylaromatic compounds are commercially available. The number averagemolecular weight of the block copolymers, prior to hydrogenation, isfrom about 20,000 to about 500,000, or from about 40,000 to about300,000.

The average molecular weights of the individual blocks within thecopolymers may vary within certain limits. In most instances, the vinylaromatic block will have a number average molecular weight in the orderof about 2000 to about 125,000, or between about 4000 and 60,000. Theconjugated diene blocks either before or after hydrogenation will havenumber average molecular weights in the order of about 10,000 to about450,000, or from about 35,000 to 150,000.

Also, prior to hydrogenation, the vinyl content of the conjugated dieneportion generally is from about 10% to about 80%, or from about 25% toabout 65%, particularly 35% to 55% when it is desired that the modifiedblock copolymer exhibit rubbery elasticity. The vinyl content of theblock copolymer can be measured by means of nuclear magnetic resonance.

Specific examples of diblock copolymers include styrene-butadiene (SB),styrene-isoprene (SI), and the hydrogenated derivatives thereof.Examples of triblock polymers include styrene-butadiene-styrene (SBS),styrene-isoprene-styrene (SIS),alpha-methylstyrene-butadiene-alpha-methylstyrene, andalpha-methylstyrene-isoprene alpha-methylstyrene. Examples ofcommercially available block copolymers useful as the adhesives in thepresent invention include those available from Kraton Polymers LLC underthe KRATON trade name.

Upon hydrogenation of the SBS copolymers comprising a rubbery segment ofa mixture of 1,4 and 1,2 isomers, a styrene-ethylene-butylene styrene(SEBS) block copolymer is obtained. Similarly, hydrogenation of an SISpolymer yields a styrene-ethylene propylene-styrene (SEPS) blockcopolymer.

The selective hydrogenation of the block copolymers may be carried outby a variety of well known processes including hydrogenation in thepresence of such catalysts as Raney nickel, noble metals such asplatinum, palladium, etc., and soluble transition metal catalysts.Suitable hydrogenation processes which can be used are those wherein thediene-containing polymer or copolymer is dissolved in an inerthydrocarbon diluent such as cyclohexane and hydrogenated by reactionwith hydrogen in the presence of a soluble hydrogenation catalyst. Suchprocedures are described in U.S. Pat. Nos. 3,113,986 and 4,226,952, thedisclosures of which are incorporated herein by reference. Suchhydrogenation of the block copolymers which are carried out in a mannerand to extent as to produce selectively hydrogenated copolymers having aresidual unsaturation content in the polydiene block of from about 0.5%to about 20% of their original unsaturation content prior tohydrogenation.

In one embodiment, the conjugated diene portion of the block copolymeris at least 90% saturated and more often at least 95% saturated whilethe vinyl aromatic portion is not significantly hydrogenated.Particularly useful hydrogenated block copolymers are hydrogenatedproducts of the block copolymers of styrene-isoprene-styrene such as astyrene-(ethylene/propylene)-styrene block polymer. When apolystyrene-polybutadiene-polystyrene block copolymer is hydrogenated,it is desirable that the 1,2-polybutadiene to 1,4-polybutadiene ratio inthe polymer is from about 30:70 to about 70:30. When such a blockcopolymer is hydrogenated, the resulting product resembles a regularcopolymer block of ethylene and 1-butene (EB). As noted above, when theconjugated diene employed as isoprene, the resulting hydrogenatedproduct resembles a regular copolymer block of ethylene and propylene(EP).

A number of selectively hydrogenated block copolymers are availablecommercially from Kraton Polymers under the general trade designation“Kraton G.” One example is Kraton G1652 which is a hydrogenated SBStriblock comprising about 30% by weight of styrene end blocks and amidblock which is a copolymer of ethylene and 1-butene (EB). A lowermolecular weight version of G1652 is available under the designationKraton G1650. Kraton G1651 is another SEBS block copolymer whichcontains about 33% by weight of styrene. Kraton G1657 is an SEBS diblockcopolymer which contains about 13%w styrene. This styrene content islower than the styrene content in Kraton G1650 and Kraton G1652.

In another embodiment, the selectively hydrogenated block copolymer isof the formula:

B_(n)(AB)_(o)A_(p)

wherein n=0 or 1; o is 1 to 100; p is 0 or 1; each B prior tohydrogenation is predominantly a polymerized conjugated dienehydrocarbon block having a number average molecular weight of about20,000 to about 450,000; each A is predominantly a polymerized vinylaromatic hydrocarbon block having a number average molecular weight offrom about 2000 to about 115,000; the blocks of A constituting about 5%to about 95% by weight of the copolymer; and the unsaturation of theblock B is less than about 10% of the original unsaturation. In otherembodiments, the unsaturation of block B is reduced upon hydrogenationto less than 5% of its original value, and the average unsaturation ofthe hydrogenated block copolymer is reduced to less than 20% of itsoriginal value.

The block copolymers may also include functionalized polymers such asmay be obtained by reacting an alpha, beta-olefinically unsaturatedmonocarboxylic or dicarboxylic acid reagent onto selectivelyhydrogenated block copolymers of vinyl aromatic hydrocarbons andconjugated dienes as described above. The reaction of the carboxylicacid reagent in the graft block copolymer can be effected in solutionsor by a melt process in the presence of a free radical initiator.

The preparation of various selectively hydrogenated block copolymers ofconjugated dienes and vinyl aromatic hydrocarbons which have beengrafted with a carboxylic acid reagent is described in a number ofpatents including U.S. Pat. Nos. 4,578,429; 4,657,970; and 4,795,782,and the disclosures of these patents relating to grafted selectivelyhydrogenated block copolymers of conjugated dienes and vinyl aromaticcompounds, and the preparation of such compounds are hereby incorporatedby reference. U.S. Pat. No. 4,795,782 describes and gives examples ofthe preparation of the grafted block copolymers by the solution processand the melt process. U.S. Pat. No. 4,578,429 contains an example ofgrafting of Kraton G1652 (SEBS) polymer with maleic anhydride with2,5-dimethyl-2,5-di(t-butylperoxy)hexane by a melt reaction in a twinscrew extruder.

Examples of commercially available maleated selectively hydrogenatedcopolymers of styrene and butadiene include Kraton FG1901X, FG1921X, andFG1924X, often referred to as maleated selectively hydrogenated SEBScopolymers. FG1901X contains about 1.7% w bound functionality assuccinic anhydride and about 28%w of styrene. FG1921X contains about 1%w of bound functionality as succinic anhydride and 29%w of styrene.FG1924X contains about 13% styrene and about 1% bound functionality assuccinic anhydride.

Useful block copolymers also are available from Nippon Zeon Co., 2-1,Marunochi, Chiyoda-ku, Tokyo, Japan. For example, Quintac 3530 isavailable from Nippon Zeon and is believed to be a linearstyrene-isoprene-styrene block copolymer.

Unsaturated elastomeric polymers and other polymers and copolymers whichare not inherently tacky can be rendered tacky when compounded with anexternal tackifier. Tackifiers, are generally hydrocarbon resins, woodresins, rosins, rosin derivatives, and the like, which when present inconcentrations ranging from about 40% to about 90% by weight of thetotal adhesive composition, or from about 45% to about 85% by weight,impart pressure-sensitive adhesive characteristics to the elastomericpolymer adhesive formulation. Compositions containing less than about40% by weight of tackifier additive do not generally show sufficient“quickstick,” or initial adhesion, to function as a pressure-sensitiveadhesive, and therefore are not inherently tacky. Compositions with toohigh a concentration of tackifying additive, on the other hand,generally show too little cohesive strength to work properly in mostintended use applications of constructions made in accordance with theinstant invention.

It is contemplated that any tackifier known by those of skill in the artto be compatible with elastomeric polymer compositions may be used withthe present embodiment of the invention. One such tackifier, founduseful is Wingtak 10, a synthetic polyterpene resin that is liquid atroom temperature, and sold by the Goodyear Tire and Rubber Company ofAkron, Ohio. Wingtak 95 is a synthetic tackifier resin also availablefrom Goodyear that comprises predominantly a polymer derived frompiperylene and isoprene. Other suitable tackifying additives may includeEscorez 1310, an aliphatic hydrocarbon resin, and Escorez 2596, a C₅-C₉(aromatic modified aliphatic) resin, both manufactured by Exxon ofIrving, Tex. Of course, as can be appreciated by those of skill in theart, a variety of different tackifying additives may be used to practicethe present invention.

In addition to the tackifiers, other additives may be included in thePSAs to impart desired properties. For example, plasticizers may beincluded, and they are known to decrease the glass transitiontemperature of an adhesive composition containing elastomeric polymers.An example of a useful plasticizer is Shellflex 371, a naphthenicprocessing oil available from Shell Lubricants of Texas. Antioxidantsalso may be included on the adhesive compositions. Suitable antioxidantsinclude Irgafos 168 and Irganox 565 available from Ciba-Geigy,Hawthorne, N.Y. Cutting agents such as waxes and surfactants also may beincluded in the adhesives.

The pressure sensitive adhesive may be applied from a solvent, emulsionor suspension, or as a hot melt. The adhesive may be applied to theinner surface of the shrink film by any known method. For example, theadhesive may be applied by die coating curtain coating, spraying,dipping, rolling, gravure or flexographic techniques. The adhesive maybe applied to the shrink film in a continuous layer, a discontinuouslayer or in a pattern. The pattern coated adhesive layer substantiallycovers the entire inner surface of the film. As used herein,“substantially covers” is intended to mean the pattern in continuousover the film surface, and is not intended to include adhesive appliedonly in a strip along the leading or trailing edges of the film or as a“spot weld” on the film.

In one embodiment, an adhesive deadener is applied to portions of theadhesive layer to allow the label to adhere to complex shaped articles.In one embodiment, non-adhesive material such as ink dots or microbeadsare applied to at least a portion of the adhesive surface to allow theadhesive layer to slide on the surface of the article as the label isbeing applied and/or to allow air trapped at the interface between thelabel and the article to escape.

A single layer of adhesive may be used or multiple adhesive layers maybe used. Depending on the shrink film used and the article or containerto which the label is to be applied, it may be desirable to use a firstadhesive layer adjacent to the shrink film and a second adhesive layerhaving a different composition on the surface to be applied to thearticle or container for sufficient tack, peel strength and shearstrength.

In one embodiment, the pressure sensitive adhesive has sufficient shearor cohesive strength to prevent excessive shrink-back of the label whereadhered to the article upon the action of heat after placement of thelabel on the article, sufficient peel strength to prevent the film fromlabel from lifting from the article and sufficient tack or grab toenable adequate attachment of the label to the article during thelabeling operation. In one embodiment, the adhesive moves with the labelas the shrink film shrinks upon the application of heat. In anotherembodiment, the adhesive holds the label in position so that as theshrink film shrinks, the label does not move.

The heat shrinkable film may include other layers in addition to themonolayer or multilayer heat shrinkable polymeric film. In oneembodiment, a metalized coating of a thin metal film is deposited on thesurface of the polymeric film. The heat shrinkable film may also includea print layer on the polymer film. The print layer may be positionedbetween the heat shrink layer and the adhesive layer, or the print layermay be on the outer surface of the shrink layer. In one embodiment, thefilm is reverse printed with a design, image or text so that the printside of the skin is in direct contact with the container to which thefilm is applied. In this embodiment, the film is transparent.

The labels of the present invention may also contain a layer of anink-receptive composition that enhances the printability of thepolymeric shrink layer or metal layer if present, and the quality of theprint layer thus obtained. A variety of such compositions are known inthe art, and these compositions generally include a binder and apigment, such as silica or talc, dispersed in the binder. The presenceof the pigment decreases the drying time of some inks. Suchink-receptive compositions are described in U.S. Pat. No. 6,153,288(Shih et al) and the disclosure of this patent is hereby incorporated byreference.

The print layer may be an ink or graphics layer, and the print layer maybe a mono-colored or multi-colored print layer depending on the printedmessage and/or the intended pictorial design. These include variableimprinted data such as serial numbers, bar codes, trademarks, etc. Thethickness of the print layer is typically in the range of about 0.5 toabout 10 microns, and in one embodiment about 1 to about 5 microns, andin another embodiment about 3 microns. The inks used in the print layerinclude commercially available water-based, solvent-based orradiation-curable inks. Examples of these inks include Sun Sheen (aproduct of Sun Chemical identified as an alcohol dilutable polyamideink), Suntex MP (a product of Sun Chemical identified as a solvent-basedink formulated for surface printing acrylic coated substrates, PVDCcoated substrates and polyolefin films), X-Cel (a product of Water InkTechnologies identified as a water-based film ink for printing filmsubstrates), Uvilith AR-109 Rubine Red (a product of Daw Ink identifiedas a UV ink) and CLA91598F (a product of Sun Chemical identified as amultibond black solvent-based ink).

In one embodiment, the print layer comprises a polyester/vinyl ink, apolyamide ink, an acrylic ink and/or a polyester ink. The print layermay be formed in the conventional manner by, for example, gravure,flexographic or UV flexographic printing or the like, an ink compositioncomprising a resin of the type described above, a suitable pigment ordye and one or more suitable volatile solvents onto one or more desiredareas of the film. After application of the ink composition, thevolatile solvent component(s) of the ink composition evaporate(s),leaving only the non-volatile ink components to form the print layer.

The adhesion of the ink to the surface of the polymeric shrink film ormetal layer if present can be improved, if necessary, by techniques wellknown to those skilled in the art. For example, as mentioned above, anink primer or other ink adhesion promoter can be applied to the metallayer or the polymeric film layer before application of the ink.Alternatively the surface of the polymeric film can be corona treated orflame treated to improve the adhesion of the ink to the polymeric filmlayer.

Useful ink primers may be transparent or opaque and the primers may besolvent based or water-based. In one embodiment, the primers areradiation curable (e.g., UV). The ink primer may comprise a lacquer anda diluent. The lacquer may be comprised of one or more polyolefins,polyamides, polyesters, polyester copolymers, polyurethanes,polysulfones, polyvinylidine chloride, styrene-maleic anhydridecopolymers, styrene-acrylonitrile copolymers, ionomers based on sodiumor zinc salts or ethylene methacrylic acid, polymethyl methacrylates,acrylic polymers and copolymers, polycarbonates, polyacrylonitriles,ethylene-vinyl acetate copolymers, and mixtures of two or more thereof.Examples of the diluents that can be used include alcohols such asethanol, isopropanol and butanol; esters such as ethyl acetate, propylacetate and butyl acetate; aromatic hydrocarbons such as toluene andxylene; ketones such as acetone and methyl ethyl ketone; aliphatichydrocarbons such as heptane; and mixtures thereof. The ratio of lacquerto diluent is dependent on the viscosity required for application of theink primer, the selection of such viscosity being within the skill ofthe art. The ink primer layer may have a thickness of from about 1 toabout 4 microns or from about 1.5 to about 3 microns.

A transparent polymer protective topcoat or overcoat layer may bepresent in the labels of the invention. The protective topcoat orovercoat layer provide desirable properties to the label before andafter the label is affixed to a substrate such as a container. Thepresence of a transparent topcoat layer over the print layer may, insome embodiments provide additional properties such as antistaticproperties stiffness and/or weatherability, and the topcoat may protectthe print layer from, e.g., weather, sun, abrasion, moisture, water,etc. The transparent topcoat layer can enhance the properties of theunderlying print layer to provide a glossier and richer image. Theprotective transparent protective layer may also be designed to beabrasion resistant, radiation resistant (e.g, UV), chemically resistant,thermally resistant thereby protecting the label and, particularly theprint layer from degradation from such causes. The protective overcoatmay also contain antistatic agents, or anti-block agents to provide foreasier handling when the labels are being applied to containers at highspeeds. The protective layer may be applied to the print layer bytechniques known to those skilled in the art. The polymer film may bedeposited from a solution, applied as a preformed film (laminated to theprint layer), etc.

When a transparent topcoat or overcoat layer is present, it may have asingle layer or a multilayered structure. The thickness of theprotective layer is generally in the range of about 12.5 to about 125microns, and in one embodiment about 25 to about 75 microns. Examples ofthe topcoat layers are described in U.S. Pat. No. 6,106,982 which isincorporated herein by reference.

The protective layer may comprise polyolefins, thermoplastic polymers ofethylene and propylene, polyesters, polyurethanes, polyacryls,polymethacryls, epoxy, vinyl acetate homopolymers, co- or terpolymers,ionomers, and mixtures thereof.

The transparent protective layer may contain UV light absorbers and/orother light stabilizers. Among the UV light absorbers that are usefulare the hindered amine absorbers available from Ciba Specialty Chemicalunder the trade designations “Tinuvin”. The light stabilizers that canbe used include the hindered amine light stabilizers available from CibaSpecialty Chemical under the trade designations Tinuvin 111, Tinuvin123, (bis-(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl)sebacate;Tinuvin 622, (a dimethyl succinate polymer with4-hydroxy-2,2,6,6-tetramethyl-1-piperidniethanol); Tinuvin 770(bis-(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate); and Tinuvin 783.Additional light stabilizers include the hindered amine lightstabilizers available from Ciba Specialty Chemical under the tradedesignation “Chemassorb”, especially Chemassorb 119 and Chemassorb 944.The concentration of the UV light absorber and/or light stabilizer is inthe range of up to about 2.5% by weight, and in one embodiment about0.05% to about 1% by weight.

The transparent protective layer may contain an antioxidant. Anyantioxidant useful in making thermoplastic films can be used. Theseinclude the hindered phenols and the organo phosphites. Examples includethose available from Ciba Specialty Chemical under the tradedesignations Irganox 1010, Irganox 1076 or Irgafos 168. Theconcentration of the antioxidant in the thermoplastic film compositionmay be in the range of up to about 2.5% by weight, and in one embodimentabout 0.05% to about 1% by weight.

A release liner may be adhered to the adhesive layer to protect theadhesive layer during transport, storage and handling prior toapplication of the label to a substrate. The liner allows for efficienthandling of an array of individual labels after the labels are die cutand the matrix is stripped from the layer of facestock material and upto the point where the individual labels are dispensed in sequence on alabeling line. The release liner may have an embossed surface and/orhave non-adhesive material, such as microbeads or printed ink dots,applied to the surface of the liner.

Process

The process of applying the labels to articles or containers involvesnon-traditional operations and equipment. The process begins withtraditional dispensing equipment that separates the label from therelease liner via a peel plate or tip that presents the label withexposed adhesive to the container or article to be decorated. Referringto FIGS. 6A to 6D, the label 62, which has a central portion 61 and aperipheral portion 63 surrounding the central portion and having anouter boundary defined by the label edges, is contacted to the container60 initially by applying pressure to the label in the central portion.Having the initial tack point(s) 64 located in a more central portion ofthe label rather than on the leading edge or peripheral portion of thelabel facilitates a more even distribution of any darts or wrinklesformed between the leading and trailing edges of the applied label. Thisin turn facilitates removal of the darts or wrinkles with theapplication of heat.

For those articles having both compound curves and relatively planarregions, the label may be initially contacted with the container not ona compound curve, but closer to or within a relatively planar area ofthe container surface.

In one embodiment, the label is pre-heated to soften the shrink filmand/or activate the adhesive layer.

Pressure is applied to the transferred label with a series of brushes,rollers, wipers, squeegees, pneumatic rollers, or walking beam in acenter outward direction, as indicated by arrows 65, to obtain intimatecontact between the label and the container or article. This process isreferred to herein as “wipe down” of the label. The center to edgewiping motion forces any air trapped beneath the label to the outeredges, as indicated by arrows 66, and creates smaller, more evenlydistributed darts at the edges of the label. As the label covers thecomplex curves of the article, excess label material accumulates in theform of darts, pleats, channeling, bubbling and other applicationdefects generally in the peripheral portion of the label. Heat isapplied to at least a portion of the label to fully and smoothly adherethe label to the container as shown in FIG. 6D.

In one embodiment, pressure is applied to the label using a walking beamsystem equipped with a foam roller or foam covered beam. The foam rolleror beam applies downward pressure in the longitudinal direction to thecentral region of the label and then proceeds to the outer edges of thelabel, directing any air trapped under the label and the pleats,wrinkles and/or other defects to the outer edges of the label. Thisembodiment is illustrated in FIG. 7, wherein container 70 having label71 applied thereto, is positioned on lower foam block 72 a of a walkingbeam. Upper foam block 72 b applies downward pressure onto label 71 oncontainer 70 to push air from under the central portion of the label tothe periphery of the label as label and container are compressed betweenthe foam blocks of the walking beam.

Once the label is applied and initial wipe down is completed, the excesslabel material darts and defects are eliminated by heating at least aportion the label to shrink the darts and/or wrinkles. The label may beheated via passage through a heat tunnel, forced air, steam tunnel,direct contact heat pads or forms. In one embodiment, the label isheated to a temperature of at least 40° C. In one embodiment, the labelis heated to at least 60° C., or at least 70° C., or at least 80° C.

A subsequent wipe down of the label may be performed to eliminate anyremaining darts or wrinkles in the label. Pressure is again applied tothe label in a center outward direction to the label. The second wipedown can be performed by a series of rollers, wipers, squeegees,brushes, pneumatic rollers or a walking beam. The subsequent wipe downmay be performed concurrently with the application of heat to the label,or subsequent to the application of heat.

When applying the label to an article or container, the label may beinitially tacked to the article by applying pressure in a contact regionof the label, and then applying pressure across the label in a directionto a first edge of the label. The contact region may be in the center ofthe label or may be proximate to a second edge of the label opposite tothe first edge. For example, initial contact may be made in the centerof the label and then pressure is applied in an outward direction to theedges or periphery of the label. Alternatively, initial contact may bemade near one edge of the label and then pressure applied across thelabel to the opposite edge of the label. When applying the label to thearticle or container, it is desirable to move the excess label material,i.e., the darts or wrinkles, to at least one label edge. The excessmaterial is typically moved in the direction of the compound curve(s),where the heat applied to the label will shrink the label and allow itto conform to the compound curve and eliminate any darts or wrinklesformed. Heat and pressure may be applied to the label simultaneously.

In one embodiment of the invention, the method of applying a label to anarticle includes the steps of: providing an article having a surfaceincluding at least one compound curve; providing a label including (i) aheat shrinkable film having an inner surface and an outer surface; and(ii) a layer of pressure sensitive adhesive on the inner surface of theheat shrinkable film, wherein the label has a first edge and a contactregion; contacting the adhesive layer in the contact region with thearticle; and applying heat and pressure simultaneously to the label in adirection from the contact region to the first edge such that the firstedge of the label adheres to article and the label shrinks to conform tothe compound curve of the article, wherein the heat and pressure areapplied by a heated conformable membrane. The contact region may belocated in or near the center of the label. Alternatively, the contactregion may be proximate to a second edge of the label opposite the firstedge.

The heated membrane may, in one embodiment, be pressed against the labelon the article or container by a walking beam having a heated bladder.Referring to FIG. 8, the walking beam 80 includes a containment box 82a, 82 b on each of its longitudinal members 81 a, 81 b, the containmentbox having a flexible and conformable membrane 83 a, 83 b at its innersurface to create a bladder 87 a, 87 b. The heated membrane 83 a, 83 bis positioned onto the passing labeled container 85 via a walking beammechanism, with the container 85 in a horizontal or vertical position.The membrane may be constructed of a conformable, high temperature,non-porous high-release material. The bladder 87 a, 87 b is filled witha heated liquid or gas so as to heat the membrane 83 a, 83 b. The heatfrom the membrane 83 a, 83 b is transferred to the label 86 on thecontainer 85. A label may be applied to one or both sides of thecontainer. For the sake of simplicity, a label is applied to only onesurface of the container in FIG. 8

In this method, the label 86 is first applied to a center section of thecontainer 85 with a standard peel tip dispensing process (not shown)with leading and trailing edges not tacked down. The labeled container85 is moved into the walking beam station 80 via a conveyor 84 and thewalking beam closes in on one or more containers 85. Pressure from theheated, expanded bladder 87 a is applied to the label 86 on thecontainer 85 at an initial contact point in the center of the label inan outward direction to the edges of the label, pushing any air underthe label from the center of the label to the outer edges of the label.The bladder is pre-heated to a target temperature based on the linespeed and label material used. The heat from the bladder membrane 83asoftens the label 86 and shrinks the label. The simultaneous applicationof heat and pressure from the bladder membrane 83 a to the label forcesthe label to conform to the surface of the container 85, including thecompound curve(s) of the container. An optional subsequent heating stepmay be used to further shrink the label. An advantage of this method isthat labels may be applied to a wide variety of container shapes withoutthe need for retooling. In addition, high speed processing is possibledue to the continuous heat recovery of the bladder.

FIGS. 9A and 9B illustrate another embodiment of the invention wherein awalking beam with a heated cavity is used to apply the label to thearticle or container. For illustration purposes, only one side of thewalking beam conveyor is shown. The walking beam containment box 90includes an internally heated bottle-shaped cavity 91. The shape of thecavity 91 is configured to correspond to the container or article 92 towhich the label 93 is applied. The cavity is preheated to a targettemperature based on the line speed and label material selected. Theheated cavity is positioned onto the passing labeled container via awalking beam conveyor. The walking beam may contain a single or multiplecavities for applying heat and pressure to a single or multiplecontainers. The labeled surface of the container 92 faces the interiorof the cavity 91. The interior of the cavity 91 may be lined with aconformable, soft material such as a silicon rubber sheet havingimbedded electric heater wires vulcanized in place. Heat and pressurefrom the cavity 91 softens the label 93 and shrinks the label. Pressureapplied by the soft cavity forces air from under the label to the edgesof the label to eliminate bubbles. The simultaneous application of heatand pressure from the heated cavity to the label 93 forces the label toconform to the surface of the container, including the compound curve(s)of the container. The excess label material, i.e., darts and wrinkles,are eliminated by the shrinkage of the label. An optional subsequentheating step may be used to further shrink the label. The advantage ofthis method is that the exact shape of the cavity provides full bottlecontact to enable rapid heat transfer and fill pressure to force air outfrom under the label.

FIG. 10 illustrates another embodiment of the invention for applyinglabels to a container having compound curves. In this embodiment, awalking beam containment box 100 includes an internally heated soft,flexible pad 101 suspended between at least two frame members 102 as itscontact surface. For illustration purposes, only one side of the walkingbeam conveyor is shown. The heated pad 101 is positioned onto thepassing labeled containers via a walking beam conveyor in either thevertical or horizontal direction. The label 104 is first applied to acontact point on the container with a standard peel tip dispensingprocess (not shown) with the leading and trailing edges of the label nottacked down. The container 103 with the label adhered thereto is movedinto the walking beam station via a conveyor and the walking beam movesinward to enclose the container. The heated, flexible pad 101 ispositioned to push the label 104 toward the container while removing airfrom under the label. The pad 101 is pre-heated to a target temperaturebased on the line speed and label material selected. The heated pad maybe porous or non-porous. The simultaneous application of heat andpressure from the heated pad 101 to the label 104 forces the label toconform to the surface of the container, including the compound curve(s)of the container. The heat source may be one or more of radiantelectric, IR electric, forced hot air and electric resistance heatintegrated with the heated pad. An optional subsequent heating step maybe used to further shrink the label. An advantage of this methodincludes the ability to apply labels to a wide variety of containershapes without the need for retooling.

FIGS. 11A and 11B illustrate another embodiment of the invention whereina walking beam conveyor includes a rectangular framed containment box110 having a flexible heated membrane mounted to the rectangular frame.In this embodiment, an extensible, internally heated membrane 111, suchas a silicone rubber sheet, is mounted over an open rectangular frame112 along each side of a walking beam conveyor. For illustrationpurposes, only one side of the walking beam conveyor is shown. A labelmay be applied to one or both sides of the container 113. The label 114is first applied to a contact point on the container with a standardpeel tip dispensing process (not shown) with the leading and trailingedges of the label not tacked down. The membrane 111 is mounted so thattension is applied across the membrane. The perimeter dimensions of therectangular frame 111 are larger than the overall profile of thecontainer 113 to be labeled. In one embodiment, the depth of the frameis greater than one-half the thickness of the container to be labeled toallow the container to penetrate the plane of the membrane. Theopen/close motion of the walking beam provides sufficient force to trapthe container 113 between a supported membrane 111 on each side of thewalking beam, or one side of the walking beam, to force the container113 into the frame 112 while the heated membrane 111 conforms to thesurface of the container 113. The membrane is pre-heated to a targettemperature based on the line speed and label material selected. Thedwell time of the closed walking beam can be controlled through thewalking beam station by the design of the cam system. The walking beammay contain a plurality of rectangular frames to apply labels to aplurality of containers. As the walking beam opens and reciprocates, thelabeled container may optionally be enclosed within the membranes of thewalking beam a second time for a second application of heat andpressure. The simultaneous application of heat and pressure from themembrane 111 to the label 114 forces the label to conform to the surfaceof the container 113, including the compound curve(s) of the container.An optional subsequent heating step may be used to further shrink thelabel 114. The advantage of this embodiment is that the generic shape ofthe rectangular frame allows containers having various shapes to belabeled without the necessity of providing unique frames.

FIGS. 12A and 12B illustrate an embodiment that is similar to thatillustrated in FIGS. 11A and 11B. In this embodiment, an extensible,internally heated membrane 121, such as a silicone rubber sheet, ismounted over an open frame 122 along each side of a walking beamconveyor 120. For illustration purposes, only one side of the walkingbeam conveyor is shown. The dimensions of the frame 121 are configuredto correspond to the overall profile of the container 123 to be labeledand are slightly larger to allow space for the membrane as it is pushedinto the frame 122. The membrane 121 is mounted so that tension isapplied across the membrane. In one embodiment, the depth of the frameis greater than one-half the thickness of the container to be labeled toallow the container to penetrate the plane of the membrane. Theopen/close motion of the walking beam provides sufficient force to trapthe container 123 between a supported membrane 121 on each side of thewalking beam, or one side of the walking beam, to force the container123 into the frame 122 while the heated membrane 121 conforms to thesurface of the container 123. The membrane is pre-heated to a targettemperature based on the line speed and label material selected. Thedwell time of the closed walking beam can be controlled through thewalking beam station by the design of the cam system. The walking beammay contain a plurality of shaped frames to apply labels to a pluralityof similarly shaped containers. As the walking beam opens andreciprocates, the labeled container may optionally be enclosed withinthe membranes of the walking beam a second time for a second applicationof heat and pressure. The simultaneous application of heat and pressurefrom the membrane 121 to the label 124 forces the label to conform tothe surface of the container 123, including the compound curve(s) of thecontainer. An optional subsequent heating step may be used to furthershrink the label. An advantage of this embodiment is that the shapedframe enables better conformability to the contours around the top andbottom of the containers.

FIG. 13 illustrates an embodiment of the invention wherein a walkingbeam includes a flexible porous mesh that is externally heated with hotair. In this embodiment, a walking beam containment box 130 includes anexternally heated soft, flexible mesh or fabric 131 suspended between atleast two frame members 132 as its contact surface. For illustrationpurposes, only one side of the walking beam conveyor is shown. Theheated mesh is positioned onto the passing labeled containers via awalking beam conveyor in the horizontal direction. The label 136 isfirst applied to a contact point or region on the container with astandard peel tip dispensing process (not shown) with the leading andtrailing edges of the label not tacked down. The container 135 with thelabel adhered thereto is moved into the walking beam station via aconveyor and the walking beam moves inward to enclose the container. Theheated, flexible mesh 131 is positioned to push the label 136 toward thecontainer while removing air from under the label. The mesh 131 isheated to a target temperature with a source of hot air 134 based on theline speed and label material selected. The hot air from the hot airsource 134 is blown through the pores 133 of the mesh to heat the labelon the container 135. The mesh may be constructed, for example, from amesh screen, a non-woven fabric or a thin, porous foam sheeting. Thesimultaneous application of heat and pressure from the heated mesh tothe label forces the label to conform to the surface of the container,including the compound curve(s) of the container. An optional subsequentheating step may be used to further shrink the label 136. The advantagesof this method include excellent contact with the container and heattransfer from the heated air to the labeled container. This methodenables very good recovery of heat and recovery of the shape of themesh. This embodiment may be used on a variety of container shapes andis able to achieve higher temperatures based on the thermal stability ofthe mesh material.

FIGS. 14A and 14B illustrate an embodiment of the invention wherein awalking beam 140 includes one or more containment boxes, each having anexpandable membrane 142 as its contact surface to create an expandablebladder 143. For illustration purposes, only one side of the walkingbeam conveyor is shown. The heated membrane 143 is positioned onto thepassing labeled container 145 via a walking beam mechanism, with thecontainer 145 in a horizontal or vertical position. The membrane may beconstructed of a conformable, high temperature, non-porous high-releasematerial. The bladder 143 is filled with a heated liquid or gas so as toheat the membrane 142. The heat from the membrane 142 is transferred tothe label 146 on the container 145. A label may be applied to one orboth sides of the container. A label may be applied to one or both sidesof the container.

In this method, the label 146 is first applied to a center section ofthe container 145 with a standard peel tip dispensing process (notshown) with leading and trailing edges not tacked down. The labeledcontainer 145 is moved into the walking beam station 140 via a conveyorand the walking beam closes in on one or more containers 145. Pressurefrom the heated, expanded bladder 143 is applied to the label 146 on thecontainer 145 at a contact point in the center of the label in anoutward direction to the edges of the label, pushing any air under thelabel from the center of the label to the outer edges of the label. Theexpandable bladder is pre-heated to a target temperature based on theline speed and label material used. The heat from the bladder membrane142 softens the label 146 and shrinks the label. The simultaneousapplication of heat and pressure from the bladder membrane 142 to thelabel forces the label to conform to the surface of the container,including the compound curve(s) of the container. An optional subsequentheating step may be used to further shrink the label. The advantages ofthis method include the application of labels to a wide variety ofcontainer shapes without the need for retooling. In addition, high speedprocessing is possible due to the continuous heat recovery of thebladder. Another advantage is that the application of heat and pressurein a center outward direction in both the vertical and horizontaldirection assures proper label application without generating labeldefects. Furthermore, due to the limited number of moving mechanicalcomponents, low maintenance is required.

The labeled article of the present invention may be used in a variety ofapplications, including, but not limited to personal care products,household chemical products, food and beverages, toys, electronics,pharmaceuticals, health care products, industrial products andappliances.

EXAMPLES

The following examples are intended only to illustrate methods andembodiments in accordance with the invention, and as such should not beconstrued as imposing limitations upon the claims.

Example 1

A pressure sensitive shrink label is constructed from a 3 mil thick lowdensity polyethylene multilayer shrink film designated CorrTuff fromSealed Air. The film is coated with an acrylic emulsion adhesive S692Nfrom Avery Dennison. The adhesive is carried on a paper Glassine BG-40silicone coated release liner. The label is oversized, having thedimensions of approximately 5×3.5 inches, which is 20% greater than theindustry standard recommended label size for the bottle to which thelabel is applied.

A 15 oz Johnson & Johnson Baby Lotion bottle having compound curves isfilled with water, capped and processed through a Label-Aire 9000 serieslabeler at 100 bottles per minute (BPM). The labeler has dual-feedscrews with matched speed top and lower belts with Label-Aire 2115-CDlabeler heads with high torque stepper motor drive. The labels arepressed down with a walking beam type wipe down apparatus providingstraight out, center outward forces to direct the trapped air beneaththe label and resultant dart/pleat defects to the edge of the label. Theoversized label as applied to the bottle initially results inunacceptable small darts and pleat defects around the perimeter of thelabel. The labeled bottle is then processed through a Leister hot forcedair, conveyor wipe down system at 100 bpm. High velocity 260° C. hot airheats the bottle and label to 50° C., shrinking and taking up the excesslabel material darts and pleats down to the bottle surface. The label iswiped down with a walking beam for good label contact. The darts shrinkand are easily wiped flat after application of heat.

The finished labeled bottle with larger label area and larger graphicscontent is smoothly wiped down without the darts, pleats, ridges orwrinkle defects present in typical pressure sensitive oversized labels.The darts do not return upon aging. Table 1 below shows the propertiesof the label components.

Example 2

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 2 mil thick polypropylenemultilayer shrink film designated CZPA 200 from Innovia is applied tothe bottle having compound curves. After initial wipe down, medium sizeddarts are formed. High velocity hot air heats the bottle and label to100° C. The darts shrink and are easily wiped flat after application ofheat. The darts do not return after aging.

Example 3

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 2 mil thick polylactic acidsingle layer shrink film designated EARTHFIRST PLA from PlasticSuppliers is applied to the bottle having compound curves. After initialwipe down, medium sized darts are formed. High velocity hot air heatsthe bottle and label to 70° C. The darts shrink and are easily wipedflat after application of heat. The darts do not return after aging.

Comparative Example 4

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 2 mil thick machine directionoriented polypropylene single layer roll-on-shrink-on film from AveryDennison is applied to the bottle having compound curves. High velocityhot air heats the bottle and label to 70° C. The darts formed at the topand bottom of the label shrink upon application of heat and are easilywiped down, while the darts formed at the leading and trailing edgesremain. The removed darts do not return upon aging.

Comparative Example 5

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 1.9 mil thick transversedirection oriented polyvinyl chloride single layer film designated PentaLabel from Kloeckner is applied to the bottle having compound curves.High velocity hot air heats the bottle and label to 60° C. The dartsformed at the leading and trailing edges of the label shrink uponapplication of heat and are easily wiped down, while the darts formed atthe top and bottom of the label remain. The removed darts do not returnupon aging.

Comparative Example 6

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 2 mil thick transversedirection oriented glycol modified polyethylene terephthalate (PETG)single layer film designated Fusion 1775E from Mitsubishi is applied tothe bottle having compound curves. High velocity hot air heats thebottle and label to 50° C. The darts formed at the leading and trailingedges of the label shrink upon application of heat and are easily wipeddown, while the darts formed at the top and bottom of the label remain.The removed darts do not return upon aging.

Comparative Example 7

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 1.4 mil thick machinedirection oriented polyvinyl chloride single layer film designatedMF-L243/01 from Kloechner is applied to the bottle having compoundcurves. High velocity hot air heats the bottle and label to 60° C. Thefilm does not conform to the container. Initial wipe down is poor withmany darts formed in all directions. The darts and ridges remain afterthe application of heat and a second wipe down. The film exhibitsexcessive shrink back.

Comparative Example 8

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 2.0 mil thick polypropylenemultilayer film designated BTNY from Vifan is applied to the bottlehaving compound curves. High velocity hot air heats the bottle and labelto 100° C. The darts formed do not shrink completely at high temperatureand do not entirely wipe down flat. The darts return upon aging.

Comparative Example 9

In accordance with the process described in Example 1, a pressuresensitive shrink label constructed from a 3.4 mil thick medium densitypolyethylene (MDPE) multilayer film designated PE 85 from Charter Filmsis applied to the bottle having compound curves. High velocity hot airheats the bottle and label to 100° C. The darts formed do not shrinkcompletely at high temperature and do not entirely wipe down flat. Thedarts return upon aging.

TABLE L&W Film Ult Stiff- Poly- Construc- Tensile Modulus ness Shrink:Shrink: Adhe- Ex. Grade mer tion Process Suppliers Gauge (PSI) (PSI)(mN) MD TD sive Liner 1 CorrTuff LDPE single double Sealed Air 3.010,000 30,000 26 40%  49%  S692N BG40 layer bubble MD MD MD (106 C.)(106 C.) glassine 20,000 30,000 24 70%  69%  CD CD CD (120 C.) (120 C.)2 CZPA 200 PP multi- double Innovia 2.0 20,000 100,000 24 10%  0% S692N1.2 mil layer bubble MD MD MD (106 C.) (106 C.) PET 22,000 130,000 1814%  10%  CD CD CD (120 C.) (120 C.) 3 EARTHFIRST Poly single blownPlastic 2.0 8,000 300,000 44 7% 12%  S692N 1.2 mil PLA Lactic layerSuppliers MD MD MD (106 C.) (106 C.) PET Acid 8,000 300,000 60 8% 14% CD CD CD (120 C.) (120 C.) Comp. Med Shrink PP single MDO Avery PPD 2.0— 200,000 30 14%  0% S692N 1.2 mil 4 ROSO Film layer MD MD (106 C.) (106C.) PET 123,000 26 23%  0% CD CD (120 C.) (120 C.) Comp. Penta Label PVCsingle TDO Kloeckner 1.9 7,200 — 52 4% 56%  S692N BG40 5 2.0 mil OT-layer MD MD (106 C.) (106 C.) glassine M276/41, 16,900 36 71/9400, CD CDGLGL Comp. Fusion 2.0 PETG single TDO Mitsubishi 2.0 7,250 — 70 6% 66% S692N BG40 6 mil 1775E layer MD MD (106 C.) (106 C.) glassine 29,000 30CD CD Comp. MF- PVC single MDO Kloechner 1.4 — 220,000 — 41%  0% S35061.2 mil 7 L243/01 layer MD (106 C.) (106 C.) PET WHT 150,000 45%  +3% 03/402-B CD (120 C.) (120 C.) Comp. BTNY PP multi- tenter Vifan 2.040,000 — 35 2% 0% S692N BG40 8 layer MD MD (106 C.) (106 C.) glassine20,000 65 2% 2% CD CD (120 C.) (120 C.) Comp. PE 85 MDPE multi- blownCharter 3.4 3,000 75,000 40 0% 0% S692N BG40 9 layer Films MD MD MD (106C.) (106 C.) glassine 3,500 60,000 50 4% 0% CD CD CD (120 C.) (120 C.)

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. Therefore, it is to be under stood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

1. A pressure sensitive adhesive label for application on a surfacehaving at least one compound curve, the label comprising: a heatshrinkable film having an inner surface and outer surface, and a machinedirection and a trans direction, the film having an ultimate shrinkage Sin at least one direction of at least 10% at 90° C., wherein theshrinkage in the other direction is S±20%; and a layer of pressuresensitive adhesive on the inner surface of the heat shrinkable film. 2.The label of claim 1 wherein the heat shrinkable film comprises a filmselected from polyester, polyolefin, polyvinyl chloride, polystyrene,polylactic acid, copolymers thereof and blends thereof.
 3. The label ofclaim 1 wherein the heat shrinkable film comprises a polyolefin.
 4. Thelabel claim of 1 wherein the heat shrinkable film comprises a multilayerfilm having a core layer and at least one skin layer.
 5. The label ofclaim 1 wherein the stiffness of the film is at least 5 mN in themachine direction.
 6. The label of claim 1 further comprising a printlayer between the heat shrinkable film and the adhesive layer, whereinthe heat shrinkable film is transparent.
 7. The label of claim 1 furthercomprising a print layer on the outer surface of the heat shrinkablefilm.
 8. The label of claim 7 further comprising a protective layeroverlying the print layer.
 9. The label of claim 1 wherein the adhesivelayer comprises an emulsion adhesive.
 10. The label of claim 1 whereinthe adhesive layer comprises a hot melt adhesive.
 11. The label of claim1 wherein the adhesive layer comprises a solvent based adhesive.
 12. Thelabel of claim 1 wherein the heat shrinkable film comprises a multilayercoextruded film.
 13. The label of claim 1 further comprising a releaseliner adhered to the pressure sensitive adhesive.
 14. The label of claim1 wherein the pressure sensitive adhesive layer is continuous.
 15. Thelabel of claim 1 wherein the pressure sensitive adhesive layer ispatterned and the pattern substantially covers the inner surface of thefilm.